Methods of treating OX40 mediated recall immune responses using OX40L antibodies and agents useful for identifying same

ABSTRACT

T cell memory can persist in the absence of antigen. However, some memory cells by default are subject to signals accompanying periodic antigen exposure. OX40 is essential to the extent and persistence of Th2 memory when antigen is re-encountered. In an animal model of allergic asthma, inhibiting OX40/OX40L signaling during the secondary response to inhaled antigen suppressed lung inflammation. Inhibiting OX40 at the time of memory cell reactivation reduced the longevity of memory with further inflammation prevented upon tertiary encounter with antigen.

RELATED APPLICATIONS

This application is a continuation under 35 U.S.C §120 of applicationSer. No. 13/329,811, filed Dec. 19, 2011, which is a continuation ofapplication Ser. No. 12/143,077, filed Jun. 20, 2008, now, U.S. Pat. No.8,101,175, which is a continuation of application Ser. No. 11/873,149,filed Oct. 16, 2007, now U.S. Pat. No. 7,807,156, which is acontinuation of application Ser. No. 10/661,358 filed Sep. 11, 2003, nowU.S. Pat. No. 7,291,331, which claims priority to U.S. provisionalapplication No. 60/410,534, filed on Sep. 11, 2002, the contents of eachof which are incorporated herein in their entirety.

GOVERNMENT SUPPORT

This invention was made with government support under Grant A150498awarded by the National Institutes of Health. The government has certainrights in the invention.

FIELD OF THE INVENTION

The invention relates generally to immune responses and agents usefulfor modulating immune response. More particularly, the invention relatesto recall immune responses, and methods of reducing and preventingsymptoms, such as inflammation, associated with a recall response.

BACKGROUND

The factors that regulate T cell memory are of great interest, and ofpotential significance to understanding how to augment immunity and howto suppress adverse immune reactions. Data gathered many years agopromoted the idea that the longevity of effective memory was dependenton periodic exposure to antigen (Gray, D., Matzinger, P. (1991) J ExpMed. 174:969). In contrast, more recent data have challenged this ideaand suggested that individual memory T cells can survive for extendedperiods in the absence of specific antigen, and in some cases in theabsence of any apparent signals (Lau et al., Nature (1994) 369:648;Tanchot et al., Science (1997) 276:2057; and Swain et al., Science(1999) 286:381).

Rather than one theory being incorrect, there are scenarios that mayincorporate both ideas. For example, an alternative hypothesis is that amemory T cell can persist and be functional in the absence of signalsaccompanying antigen recognition, but that when antigen is encounteredagain, the individual memory T cell is now subject to both positive andnegative signals that will dictate its further persistence and/orfurther functionality. It can be envisioned that some types of memory,such as that driving allergic asthma, are maintained in the face ofantigen insults. Although it can be argued that other types of memorymay not involve periodic exposure to antigen, at some stage those memoryT cells will be required to respond to their specific antigen and henceagain be susceptible to any positive and negative signals that accompanythat recognition event. In either case, it is therefore essential todefine the nature of those positive and negative signals.

Apart from the TCR/peptide/MHC interaction, the most likely sources ofpositive and negative signals are membrane bound molecules of the Ig andTNFR superfamilies. Although there is abundant data on the requirementof members of these families in effective priming of naïve T cells andhence dictating the development of memory T cells, there is virtually nodata on whether they can influence reactivity or persistence of a memoryT cell once it has been generated. For example, although it is widelyaccepted that the response of a naïve T cell is positively controlled bysignals from cell surface costimulatory receptors, the role ofcostimulation in regulating a memory T cell has not been established.Based on experiments in vitro a number of years ago, it was postulatedthat memory T cells are less dependent, or independent, of costimulationfor activation (Croft et al., J Immunol. (1994) 152:2675; Byrne et al.,J Immunol. (1988) 141:3249; and Luqman, M., Bottomly, K. J Immunol.(1992) 149:2300). Negative data from in vivo studies trying to blockCD28 costimulation from B7 also supported this idea (Lu et al., JImmunol. (1995) 54:1078; Gause et al., Exp Parasitol. (1996) 84:264; andHarris et al., Eur J Immunol. (1999) 29:311), while only a fewpublications have suggested that a secondary response may be susceptibleto CD28 signals (Keane-Myers et al., J Immunol. (1997) 158:2042; andTsuyuki et al., J Exp Med. (1997) 185:1671).

In contrast to costimulation through CD28, it is now clear that a numberof additional receptors exist that may be crucial to a long-lived T cellresponse. The contribution of these other pathways to maintenance andfunctionality of antigen-specific memory T cells is unknown. OX40(CD134) is one such costimulatory member, belonging to the TNFRsuperfamily. OX40 (CD134) has been shown to mediate potent costimulatoryactivity upon binding to its cognate ligand, OX40L, expressed on APC(Weinberg et al., Semin Immunol. (1998)10:471). OX40 is notconstitutively expressed on naïve T cells but is induced 24-48 hr afterrecognition of antigen (Mallett et al., EMBO J. (1990) 9:1063;Calderhead et al., J Immunol. (1993) 151:5261; Baum et al., EMBO J.(1994) 13:3992; and Gramaglia et al., J Immunol. (1998) 161:6510. OX40L,a member of the TNF family, is also inducible being expressed onactivated B cells, dendritic cells, and macrophage-like cells (Baum etal. (1994), supra; Gramaglia et al. (1998), supra; Al-Shamkhani et al.,J Biol Chem. (1997) 272:5275; Stuber et al., Immunity (1995) 2:507;Ohshima et al., J Immunol. (1997) 159:3838; and Weinberg et al., JImmunol. (1999) 162:1818).

Previous work has demonstrated that OX40 and OX40L control thedevelopment of a number of primary T cell responses (Gramaglia et al.(1998), supra, Gramaglia et al., J Immunol. (2000) 165:3043, Rogers etal., Immunity (2001) 15:445, Weinberg et al., (1999), supra, Kopf etal., Immunity (1999) 11:699, Chen et al., Immunity (1999) 11:689, Murataet al., J Exp Med. (2000) 191:365, Jember et al., J Exp Med. (2001)193:387, Akiba et al., J Exp Med. (2000) 191:375, Tsukada et al., Blood(2000) 95:2434, Higgins et al., J Immunol. (1999) 162:486, Yoshioka etal., Eur J Immunol. (2000) 30:2815, Nohara et al., J Immunol. (2001)166:2108). OX40 appears to function by suppressing T cell death bymaintaining high levels of anti-apoptotic proteins such as Bcl-xL andBcl-2 (Rogers et al., Immunity (2001) 15:445) and inhibiting expressionor activity of pro-apoptotic proteins such as Bad and Bim. Thisconclusion is supported by in vivo studies where agonist antibodiesdirected to OX40 on a responding naïve CD4 cell enhanced primary T cellexpansion and survival, promoting the development of greater numbers ofmemory T cells (Gramaglia et al., (2000), supra; Maxwell et al., JImmunol. (2000) 164:107). However, no studies have addressed whetherthese interactions are required by memory T cells.

OX40 is down-regulated after the effector phase of primary T cellresponses and returns to baseline levels within a week after initialantigen encounter. Significantly, antigen-primed CD4⁺ T cells canupregulate OX40 more rapidly than naïve T cells and the majority canre-express OX40 within four hours of antigen stimulation (Gramaglia etal. (1998), supra). Similarly, an anergic T cell, which also representsan antigen-experienced cell, albeit functionally hyporesponsive, canalso re-express OX40 at low levels and be receptive to OX40 engagementresulting in enhanced functionality (Bansal-Pakala et al., Nat Med.(2001) 7:907).

Previous studies concluded that memory T cells largely had a reducedrequirement for costimulatory signals and, therefore, may not besusceptible to interventions that target such membrane bound moleculesas OX40 (Croft, M. Curr Opin Immunol. (1994) 6:431). For example,blocking B7-CD28 interactions during secondary responses to the nematodeparasites Heligmosomoides polygyrus and Nippostrongylus brasiliensis, orimmunogenic anti-mouse IgD antibody treatment, failed to inhibit memoryTh2 responses, whereas blocking CD28 at the time of priming wassuppressive (Lu et al., J Immunol. (1995) 54:1078, Gause et al., ExpParasitol. (1996) 84:264, Harris et al., Eur J Immunol. (1999) 29:311).These and other observations therefore imply that activation of memoryTh2 cells may be costimulation, or at least B7/CD28, independent,

SUMMARY

Methods of reducing or inhibiting a recall immune response are provided.In one embodiment, a method includes administering an amount of an agentthat reduces or inhibits OX40 or OX40L signaling, expression or activitysufficient to reduce or inhibit a recall immune response. In one aspect,the immune response is mediated at least in part by OX40 or OX40 ligand(OX40L). Recall responses include any secondary, tertiary or subsequentimmune response to an antigen that occurs in any organ or tissue (e.g.,lung, spleen, lymph node or vessel, or skin).

Methods of alleviating, ameliorating, reducing and inhibiting one ormore symptoms associated with a secondary or subsequent immune responseto an antigen, including responses mediated at least in part by OX40signaling, are also provided. In one embodiment, a method includesadministering an amount of an agent that reduces or inhibits OX40 orOX40L signaling, expression or activity sufficient to alleviate orameliorate the symptom. In another embodiment, a method includesadministering an amount of an agent that reduces or inhibits OX40 orOX40L signaling, expression or activity sufficient to reduce or inhibitone or more symptoms associated with a secondary or subsequent immuneresponse. In yet another embodiment, a method includes administering anamount of an agent that reduces or inhibits an OX40 mediated T cellresponse sufficient to alleviate or ameliorate the symptom. In stillanother embodiment, a method includes administering an amount of anagent that reduces or inhibits an OX40 mediated T cell responsesufficient to reduce or inhibit the OX40 mediated T cell response,thereby reducing or inhibiting one or more symptoms associated with asecondary or subsequent immune response.

Methods of treating asthma (e.g., mediated at least in part by OX40signaling) are additionally provided. In one embodiment, a methodincludes administering to a subject having asthma an amount of an agentsufficient to reduce or inhibit OX40 or OX40L signaling, expression oractivity, thereby treating asthma. In another embodiment, a methodincludes administering to a subject having asthma an amount of an agentsufficient to reduce or inhibit OX40 mediated T cell response, therebytreating asthma.

Methods of alleviating, ameliorating, reducing and inhibiting one ormore symptoms of asthma (e.g., mediated at least in part by OX40signaling) are further provided. In one embodiment, a method includesadministering to a subject having asthma an amount of an agentsufficient to reduce or inhibit OX40 or OX40L signaling, expression oractivity, thereby alleviating or ameliorating a symptom associated withasthma. In another embodiment, a method includes administering to asubject having or suspected of having asthma an amount of an agentsufficient to reduce or inhibit OX40 or OX40L signaling, expression oractivity, thereby reducing or inhibiting one or more symptoms of asthma.In yet another embodiment, a method includes administering to a subjecthaving or suspected of having asthma an amount of an agent sufficient toreduce or inhibit OX40 mediated T cell response, thereby reducing orinhibiting one or more symptoms of asthma.

Methods of inhibiting or reducing a recall response associated withasthma (e.g., mediated at least in part by OX40 signaling) caused atleast in part by exposure to an antigen are provided. In one embodiment,a method includes administering to a subject having asthma an amount ofan agent sufficient to reduce or inhibit OX40 or OX40L signaling,expression or activity, thereby inhibiting or reducing a recall responseassociated with asthma.

Methods of preventing asthma in a subject having asthma caused at leastin part by exposure to an antigen are provided. In one embodiment, amethod includes administering to the subject an amount of an agentsufficient to reduce or inhibit OX40 or OX40L signaling, expression oractivity, thereby preventing asthma.

Methods of preventing a recall response associated with asthma in asubject having asthma caused at least in part by exposure to an antigenare also provided. In one embodiment, a method includes administering tothe subject an amount of an agent sufficient to reduce or inhibit OX40or OX40L signaling, expression or activity, thereby preventing a recallresponse associated with asthma.

Methods of decreasing inflammation (e.g., preventing or eliminatinginflammation) associated with a memory response are further provided. Inone embodiment, a method includes administering to a subject havinginflammation associated with a memory response an amount of an agentsufficient to reduce or inhibit OX40 or OX40L signaling, expression oractivity, thereby decreasing inflammation associated with a memoryresponse.

Methods of decreasing a T cell inflammatory memory response (e.g.,preventing or eliminating T cell inflammatory memory response) aremoreover provided. In one embodiment, a method includes administering toa subject having inflammation associated with a memory response anamount of an agent sufficient to reduce or inhibit OX40 or OX40Lsignaling, expression or activity, thereby decreasing a T cellinflammatory memory response.

Subjects include mammalian subjects, such as humans. Subjects furtherinclude those having, at risk of having or whom have previously had arecall response, a symptom associated with a recall response, or havebeen diagnosed as susceptible to a recall response. Fore example, asubject having one or more symptoms of asthma (e.g., allergic asthma).

Symptoms include, for example, symptoms associated with inflammationsuch as swelling, enlargement, mucus production, rash, eosinophilinfiltration, leukocyte or lymphocyte infiltration, cytokine orchemokine production, hyperplasia, inflammatory lesions or necrosis.Symptoms further include, for example, symptoms associated with asthmaand allergic asthma such as, wheezing, shortness of breath, chesttightness, cough, and sputum production, airflow restriction, airwayedema, mucus production, eosinophil infiltration of lung, leukocyteinfiltration of lung, hyperplasia of mucus secreting epithelium,inflammatory lesion of lung, goblet cell hyperplasia, or increased Th2cytokine (e.g., IL-4, IL-5, IL-9, IL-13 or IL-16) production.

Agents include, for example, molecules that bind to OX40 or OX40L (e.g.,an antibody, human or humanized, or a modified OX40 or OX40L), OX40 andOX40L subsequences, variant sequences, chimeric sequences and dominantnegative sequences; antisense nucleic acid molecules or RNAi that bindto OX40 or OX40L DNA or RNA. Agents further include cytokines (e.g.,IL-10) and molecules that directly or indirectly modulate OX40/OX40Lsignaling, expression or activity.

Methods of identifying agents that reduce or inhibit a recall immuneresponse, are provided. In one embodiment, a method includes: providinga test agent that reduces or inhibits signaling, expression or activityof OX40 or OX40 ligand (OX40L); and measuring a recall immune responsein the presence of the test agent. In another embodiment, a methodincludes: providing a test agent that binds to OX40 or OX40 ligand(OX40L); and measuring a recall immune response in the presence of thetest agent. A reduction or inhibition of a recall response identifiesthe test agent as an agent that reduces or inhibits a recall immuneresponse.

Methods of identifying agents that alleviate or ameliorate a symptomassociated with a secondary or subsequent immune response to an antigenare also provided. In one embodiment, a method includes: providing atest agent that reduces or inhibits signaling, expression or activity ofOX40 or OX40 ligand (OX40L); and measuring a symptom associated with asecondary or subsequent immune response to an antigen in the presence ofthe test agent. In another embodiment, a method includes: providing atest agent that binds to OX40 or OX40 ligand (OX40L); and measuring asymptom associated with a secondary or subsequent immune response to anantigen in the presence of the test agent. A reduction or inhibition ofa symptom associated with a secondary or subsequent immune response toan antigen identifies the test agent as an agent that alleviates orameliorates a symptom associated with a secondary or subsequent immuneresponse to an antigen. In various aspects, the recall immune responseis mediated at least in part by OX40 signaling, occurs in vivo (e.g., ina mammal)

Test agents are selected from agents as set forth herein and include,for example, modified OX40 or OX40L, OX40 and OX40L subsequences,variant sequences, chimeric sequences and dominant negative sequences,antibodies (human or humanized) an antisense nucleic acid molecule orRNAi that binds to OX40 or OX40L DNA or RNA, cytokines, and moleculesthat directly or indirectly modulate OX40/OX40L signaling, expression oractivity. Test agents further include libraries of compounds.

Methods of identifying agents that alleviate or ameliorate a symptomassociated with asthma (e.g., mediated at least in part by OX40signaling) are additionally provided. In one embodiment, a methodincludes: providing a test agent that reduces or inhibits signaling,expression or activity of OX40 or OX40 ligand (OX40L); and measuring asymptom associated with asthma in the presence of the test agent. Inanother embodiment, a method includes: providing a test agent that bindsto OX40 or OX40 ligand (OX40L); and measuring a symptom associated withasthma in the presence of the test agent. A reduction or inhibition of asymptom associated with asthma identifies the test agent as an agentthat alleviates or ameliorates a symptom associated with asthma.

Methods of identifying agents for treating asthma are provided. In oneembodiment, a method includes: providing a test agent that reduces orinhibits signaling, expression or activity of OX40 or OX40 ligand(OX40L); and measuring asthma in the presence of the test agent. Inanother embodiment, a method includes: providing a test agent that bindsto OX40 or OX40 ligand (OX40L); and measuring asthma in the presence ofthe test agent. Alleviating or ameliorating asthma identifies the testagent as an agent for treating asthma.

DESCRIPTION OF DRAWINGS

FIGS. 1A-1C show that OX40 is expressed on memory and memory effector Tcells. (A) Peribronchial lymph nodes (LN) and (B) lung expression ofOX40 on CD4/CD44lo or CD4/CD44hi T cells. (C) Total numbers of OX40positive CD4/CD44hi T cells in lymph nodes from primed mice challengedwith PBS (Alum-OVA/PBS), primed mice challenged with OVA (Alum-OVA/OVA),and unprimed mice challenged with OVA (Alum/OVA). Similar results wereobserved in 3 studies.

FIGS. 2A-2D show that anti-OX40L suppresses memory T cell induced AHRand airway inflammation. (A) Protocol for anti-OX40L administration.Unprimed control mice injected with alum alone (Alum), primed micesensitized with OVA adsorbed to alum (Alum-OVA). Mice were challenged on4 consecutive days (days 25-28; indicated by arrows) with either PBS(Group A: Alum/OVA), control IgG (Group B: Alum-OVA/IgG-OVA) oranti-OX40L (Group C: Alum-OVA/RM134L-OVA). (B) mice airwayhyperreactivity (AHR). Results are the mean percent change in Penhlevels above baseline, after increasing methacholine concentrations.Values are calculated from four mice in each group per study (similarresults were observed in 3 studies). (C) Total leukocyte numbers inbronchoalveolar lavages (BAL) at different times (0, 1, 2, 3, and 4days) after OVA challenge (indicated by arrows). (D) Total eosinophilnumbers from differential stained BAL cytospins. Results are the meannumber of cells±SEM from two separate studies (four mice per group ineach study).

FIGS. 3A-3G show that anti-OX40L inhibits lung infiltration, goblet cellhyperplasia, mucus, serum IgE and BAL Th2 cytokine production. (A)inflammation severity and (B) mucus production with groups A (□), B (▪),and C (

) corresponding to the groups in FIG. 2. Results are the mean score±SEMfrom four separate studies (four mice per group in each study). Seraanalyzed for (C) OVA-specific IgE, and BAL analyzed for (D) IL-4, (E)IL-5, (F) IL-9, and (G) IL-13. Results are the mean values±SEM from twoseparate studies (four mice per group in each study).

FIGS. 4A-4I show that OX40 signals control memory T cell responses insecondary lymphoid organs. (A, B) Lung and (C, D) lymph node cells wereassayed for proliferation (A, C) in the presence and absence of OVA (10μg/ml), (B, D) or IL-5 production to increasing concentrations of OVA(0, 10, 50 or 100 μg/ml, left to right). (Group A: Alum/OVA; Group B:Alum-OVA/IgG-OVA; Group C: Alum-OVA/RM134L-OVA). Results are themean±SEM from quadruplicate cultures and are representative of threestudies. Peribronchial lymph node (E), lung (F), and BAL (G) cells fromunimmunized and challenged mice (⋄), or OVA-immunized and challengedmice treated with control Ab (●) vs. anti-OX40L Ab (◯). T cells werestained for CD4 and OX40 and total numbers of OX40+ CD4 T cells werecalculated. Similar results were observed in 3 studies. (H) Totalleukocyte and (I) eosinophil numbers in BAL from mice given anti-OX40Lthroughout challenge (day 0), or 1, 2, or 3 days after the initialchallenge. Results are the mean±SEM from one study with four mice pergroup.

FIGS. 5A-5C show that primed OX40−/− T cells do not survive efficientlyin recall responses in vitro. OVA-specific Th2 memory cells weregenerated in vitro as described in Example 7. (A) Proliferation, (B)survival and (C) IL-4/IL-5 production of primed T cells re-stimulatedwith OVA and APCs. Data are means±SEM from triplicate cultures, andrepresentative of 2 separate studies.

FIGS. 6A-6D show that primed OX40−/− T cells do not accumulateefficiently in recall responses in vivo. OVA-specific Th2 memory cellswere generated in vitro as described in Example 7. After the last OVAchallenge, (A, B) peribronchial lymph node, and (C, D) lung wereanalyzed for CD4 T cell (A, C) division, and (B, D) accumulation. Dataare representative of 2 separate studies.

FIGS. 7A-7B show that primed OX40-deficient T cells cannot inducepronounced airway inflammation. OVA-specific Th2 memory cells weregenerated in vitro as described in Example 7. (A) Eosinophil numbers inBAL after the last OVA challenge. (B) IL-4, IL-5, and IL-13 levels inBAL with wt T cells challenged with PBS (Grp A), wt T cells challengedwith OVA (Grp B), and OX40−/− T cells challenged with OVA (Grp C).Similar results were observed in three separate studies.

FIGS. 8A-8F show that OX40/OX40L interactions control both latesecondary and tertiary recall responses to inhaled antigen. (A)Immunization Protocol A (Example 9) for secondary response of latememory T cells. Unprimed control mice with alum alone (Alum), primedmice with OVA adsorbed to alum (Alum-OVA). OVA challenge (days 60-64;indicated by arrows). PBS (Group A: Alum/OVA), control IgG (Group B:Alum-OVA/IgG-OVA) or anti-OX40L (Group C: Alum-OVA/RM134L-OVA)administered on each challenge day (indicated by filled symbols). (D)Immunization Protocol B (Example 9) for tertiary response of late memoryT cells. Unprimed control mice with alum alone (Alum), primed mice withOVA adsorbed to alum (Alum-OVA). OVA challenge in a secondary response(days 25-29). Mice challenged in a tertiary response with OVA (days120-124; indicated by arrows). PBS (Group A: Alum/OVA), control IgG(Group B: Alum-OVA/IgG-OVA) or anti-OX40L (Group C: Alum-OVA/RM134L-OVA)administered on each challenge day (indicated by filled symbols). (B, E)Total leukocyte, and (C, F) eosinophil numbers in BAL from mice in (B,C) Protocol A, and (E, F) Protocol B. Individual responses of 4 mice ineach group are illustrated.

DETAILED DESCRIPTION

The invention is based at least in part on the discovery that antigenexposure markedly up-regulates OX40 expression on memory Th2 cells.Signaling through OX40 is critical for induction of inflammation in lungand mucosal immune responses. In addition, OX40/OX40 ligand (OX40L)signaling induces asthmatic-like reactions including airwayhyper-reactivity, mucus production, cytokine production and eosinophilinfiltration. Thus, OX40/OX40L signaling during antigen recognitioncontributes to functional memory and recall immune response. T cells cantherefore be regulated by OX40/OX40L and consequently, reducing,inhibiting or blocking OX40/OX40L signaling, expression or activity canreduce, inhibit or block a recall immune response, and one or moreundesirable or adverse symptoms and physiological complicationsassociated with recall immune response.

In accordance with the invention, there are provided methods ofreducing, inhibiting and preventing a recall immune response to anantigen. In one embodiment, a method includes administering an amount ofan agent sufficient to reduce or inhibit or prevent OX40 or OX40Lsignaling, expression or activity. In one aspect, the recall response ismediated at least in part by OX40 signaling (e.g., OX40 or OX40L). Inanother aspect, the recall response is associated with asthma (e.g.,caused at least in part by exposure to an antigen). In various aspects,agents include, for example, a cytokine such as IL-10; a molecule thatbinds to OX40 or OX40L, such as modified OX40/OX40L (e.g., subsequence,variant, fusion or dominant negative) or OX40/OX40L antibodies; andOX40/OX40L nucleic acid including antisense and RNAi. In an additionalaspect, the agent is administered to a mammalian subject (e.g., ahuman).

As used herein, “recall response,” “recall immune response,” “memoryresponse,” “memory immune response” and grammatical variations thereofmeans an immune response to an antigen to which a subject has previouslybeen exposed. A recall or memory response is therefore an immuneresponse subsequent to the initial antigen exposure and immune response.For example, a recall response may occur following exposure of thesubject to the antigen for a second (secondary), third (tertiary),fourth, fifth, sixth, seventh, eighth, ninth, tenth, or any subsequentantigen exposure.

A recall or memory response is distinguished from a primary response toan antigen; a primary response is an immune response that occurs when asubject is exposed to an antigen for the first time. In a primaryresponse, naïve T cells expand. In contrast, recall immune responses arebelieved to be attributed to reactivation of long-lived, antigen-primedT lymphocytes that arise from differentiated effector T cells in aquiescent state. Thus, a “recall response” is an immune response inwhich antigen-primed Th2 cells participate.

In the case of allergens, the primary immune response is a T-helper celltype 2 (Th2) response, which occurs prenatally. During the early yearsof life the immune system matures, which is primarily determined bygenetic susceptibility but also influenced by exposure to allergens andinfections. The development of an allergy results from repeated antigenexposure and an inappropriate response to environmental signals thatresult in an inability to dampen Th2 memory responses.

In the particular example of allergic asthma, the response can beconsidered in two-stages. The first involves the development ofallergen-specific immunological memory against inhaled allergens, whichhappens during childhood and polarizes the immune response towards a Th2phenotype making individuals more prone to developing allergicinflammation. The second involves consolidation and maintenance of thispolarized Th2 response, leading to a state of chronic airwayinflammation.

In the case of viruses and bacteria, the immune response is a Th1response. Th1 recall responses occur upon secondary or subsequentexposure to the viral or bacterial antigen. Th1 responses are associatedwith the production of different cytokines, such as IFNγ, TNF, IL-2 andIL-12. Immune cells that participate in Th1 responses includeneutrophils and macrophages. Th1 recall responses occur in variousorgans and tissues, including lung, upon secondary or subsequentexposure to viral or bacterial antigen.

Recall immune responses can result in undesirable or adverse symptomsand physiological complications, such as inflammation. BecauseOX40/OX40L signaling participates in recall response, modulating(increasing or decreasing) OX40/OX40L signaling, expression or activityprovides a means with which to modulate one or more symptoms (i.e.,undesirable or adverse symptoms) and physiological complicationsassociated with recall responses (e.g., allergic responses).

Thus, the invention provides methods of alleviating or ameliorating oneor more symptoms (i.e., undesirable or adverse symptoms) andphysiological complications associated with a secondary or subsequentimmune response, and methods of alleviating or ameliorating one or moresymptoms (i.e., undesirable or adverse symptoms) and physiologicalcomplications associated with a secondary or subsequent immune response.In one embodiment, a method includes administering an amount of an agentsufficient to reduce or inhibit or prevent OX40 or OX40L signaling,expression or activity, thereby alleviating or ameliorating one or moresymptoms associated with a secondary or subsequent immune response(e.g., inflammation). In one aspect, the secondary or subsequent immuneresponse is mediated at least in part by OX40 signaling (e.g., OX40 orOX40L). In various additional aspects, agents include, for example, acytokine such as IL-10; a molecule that binds to OX40 or OX40L, such asmodified OX40/OX40L (e.g., subsequence, variant, fusion or dominantnegative) or an OX40/OX40L antibody; and an OX40/OX40L nucleic acidincluding antisense and RNAi.

Further provided are methods of reducing, inhibiting and preventing oneor more symptoms associated with a secondary or subsequent immuneresponse to an antigen. In one embodiment, a method includesadministering an amount of an agent sufficient to reduce or inhibit orprevent OX40/OX40L signaling, expression or activity to reduce orinhibit or prevent one or more symptoms of associated with a secondaryor subsequent immune response to an antigen. In another embodiment, amethod includes administering an amount of an agent sufficient to reduceor inhibit or prevent OX40 mediated T cell response, thereby reducing orinhibiting or preventing one or more symptoms associated with asecondary or subsequent immune response. In one aspect, OX40 mediated Tcell response contributes to inflammation.

As used herein, the term “OX40 mediated T cell response,” means thatOX40 or OX40L signaling, expression or activity stimulates or inducesrecall response in which antigen experienced (memory) Th2 cellsparticipate. This T cell response can in turn contribute to inter alia,inflammation, cytokine production (associated with Th2 cells), andeffector cell infiltration of the affected region of the organ ortissue.

Additionally provided are methods of reducing, inhibiting and preventingone or more symptoms (i.e., undesirable or adverse symptoms) of asthma.In one embodiment, a method includes administering to a subject havingor suspected of having asthma an amount of an agent sufficient toreduce, inhibit or prevent OX40 or OX40L expression or activity, therebyreducing, inhibiting or preventing one or more symptoms of asthma. Inanother embodiment, a method includes administering to a subject havingor suspected of having asthma an amount of an agent sufficient toreduce, inhibit or prevent an OX40 mediated T cell response, therebyreducing, inhibiting or preventing one or more symptoms of asthma. Inone aspect, OX40 mediated T cell response contributes to inflammation.In another aspect, the symptom is caused at least in part by exposure toan antigen, e.g., a secondary or subsequent exposure.

The invention therefore further provides methods of treating andpreventing asthma. In one embodiment a method includes administering toa subject having asthma an amount of an agent sufficient to reduce orinhibit or prevent OX40 or OX40L expression or activity, therebytreating or preventing asthma. In another embodiment, a method includesadministering to a subject having asthma an amount of an agentsufficient to reduce or inhibit or prevent OX40 or OX40L signaling,expression or activity, thereby alleviating or ameliorating a symptomassociated with asthma. In yet another embodiment, a method includesadministering to a subject having asthma an amount of an agentsufficient to reduce or inhibit or prevent an OX40 mediated T cellresponse, thereby treating asthma. Particular aspects include acuteasthmatic episodes or chronic asthma, for example, a subject thatexhibits one or more mild, moderate or severe symptoms (i.e.,undesirable or adverse symptoms) or physiological complicationsassociated with or caused by asthma. In another aspect, asthma isallergic asthma.

Undesirable or adverse symptoms and physiological complicationsalleviated or ameliorated in a method of the invention include anyundesirable or adverse affect associated with or caused by a recallimmune response, such as symptoms associated with an allergic reaction.Particular non-limiting examples include swelling (edema), enlargement,mucus production, dermatitis (rash), eosinophil infiltration of tissueor organ, leukocyte or lymphocyte infiltration of tissue or organ,undesirable cytokine or chemokine production (e.g., Th2 cytokineoverproduction), tissue or organ hyperplasia, Inflammatory lesions ornecrosis of affected region of tissue or organ.

Methods of the invention include any cell type, tissue or organ affectedby a recall immune response. Specific non-limiting examples includepulmonary tissue (lung), respiratory tract (larynx, trachea, bronchialtree, nasal cavity, paranasal sinuses, nasopharynx and pharynx), spleen,lymph nodes and lymphatic vessels (e.g., gut-associated lymph), cardiac(heart) tissue, and dermal tissue (skin).

Methods of the invention include any allergic disease or immune responseaffecting any cell type, tissue or organ. For example, an allergicdisease or immune response associated with a recall response mediated,at least in part, by OX40/OX40L signaling. Specific non-limitingexamples include allergic asthma, allergic rhinitis, atopic dermatitis,and gastro-intestinal allergies.

In lung, symptoms alleviated or ameliorated in a method of the inventioninclude one or more symptoms associated with asthma, such as airway(upper or lower) hyper-reactivity (AHR)—wheezing, shortness of breath,chest tightness, cough, and sputum production, airflowobstruction/restriction (mild, moderate or severe bronchoconstriction),airway edema and mucus production. At the cellular level, symptoms thatcan be alleviated include eosinophil infiltration of lung, leukocyteinfiltration of lung, hyperplasia of mucus secreting epithelial cells,inflammatory lesions of lung, goblet cell hyperplasia, and undesirableor increased Th2 cytokine production (e.g., IL-4, IL-5, IL-9, IL-13 andIL-16).

In nasopharynx, pharynx and sinuses, symptoms alleviated or amelioratedin a method of the invention include one or more symptoms of allergicrhinitis (AR), otitis media, abnormal facial development, orthodonticproblems, eustachian tube dysfunction and sinusitis. AR is alsoassociated with asthma and, as such, one or more symptoms of AR can bealleviated or ameliorated in accordance with the invention.

In spleen, symptoms alleviated or ameliorated in a method of theinvention include enlargement (splenomegaly), hypersplenism,hyperplasia, fibrosis, abscesses and rupture.

In lymph node, symptoms alleviated or ameliorated in a method of theinvention include swelling (lymphedema), enlargement, andneo-organogenesis.

In heart, symptoms alleviated or ameliorated in a method of theinvention include one or more symptoms of a cardiomyopathy (myocarditis,hypertrophy, dilation and contractile dysfunction).

In skin, symptoms alleviated or ameliorated in a method of the inventioninclude one or more symptoms of dermatitis (irritant and allergictypes). Dermatitis (topic) or eczema can be manifested by itchingerythema, papules, and vesicles in acute phase, and dryness,hyperkeratosis, and fissures in chronic phase. Eczematous lesions arecharacterized by a mononuclear infiltrate consisting mainly of T cellsin the dermis and epidermis. Infiltrating T cells eventually causekeratinocyte apoptosis.

Assays for detecting the presence and severity of symptoms include, forexample, measuring AHR and flow cytometry (Example 1), histologicalanalysis (Example 4), IgE and Th2 cytokine production (Examples 1 and5), and T cell accumulation in the affected organ or tissue (Example 6).Additional assays are known in the art and include, for example, lungfunction (LF), skin test or blood test for allergen-specific IgEs byradioallergosorbent (RAST), atopy patch test (APT) and skin prick test(SPT) techniques, total serum IgE, screening of basophil activation (BATor FAST), assays for leukotriene LTC4 release (CAST), measurement ofplasma histamine, serum tryptase, serum ECP, urinary EDN, assay of fecalIgEs, IgG precipitins for organic dusts. Other tests are known in theart (see, e.g., Volcheck G W, Postgrad Med. (2001) 109:71-2, 77-8, 84-5;Basketter et al., Food Chem Toxicol. (2001) 39:621; Steiling et al.,Food Chem Toxicol. 2001 39:293; and Passali and Bellussi, Allergy.(1997) 52(33 Suppl):22).

As used herein, the term “ameliorate” or “alleviate,” when used inreference to an undesirable or adverse symptom or complication(physiological or psychological), means a detectable or measurabletherapeutic benefit to a subject. A therapeutic benefit is any objectiveor subjective transient or temporary, or longer term improvement in thesubject's physiological or psychological condition. For example, asatisfactory clinical endpoint is achieved when there is an incrementalimprovement in the subjects condition, or a reduction or stabilization(inhibiting a progression or worsening of the condition) of thefrequency, severity or duration of one or more undesirable or adversesymptoms (i.e., undesirable or adverse symptoms) or a physiological orpsychological complication associated with or caused by the condition,or a stabilization, inhibition or reversal of one or more of thephysiological, biochemical or cellular manifestations or characteristicsassociated with or caused by the condition.

To ameliorate or alleviate one or more symptoms and complicationsassociated with a recall immune response therefore includes anyreduction, inhibition, stabilization or prevention of an undesirable oradverse symptom or physiological or psychological complicationassociated with or caused by a recall immune response. Thus,“ameliorate”- and “alleviate” does not require complete ablation of allundesirable or adverse symptoms or physiological or psychologicalcomplications associated with or caused by a recall response. Forexample, in the case of asthma, inhibiting or reducing the severity orincidence (frequency) of acute asthmatic episodes provides a therapeuticbenefit (e.g., less frequent bouts or a reduction from moderate to mildasthmatic episodes) even though complete ablation of asthma may notresult. An improvement in a subjects' subjective feeling, such asincreased confidence, reduced depression, increased participation inoutdoor or physical activities, and improved psychological well being,are also examples of a therapeutic benefit.

The term “sufficient,” when used in reference to “amount” means thequantity effective to produce the desired effect, for example, a“therapeutic effect.” Thus, for example, a “sufficient amount” will beeffective to inhibit, reduce, or prevent, one or more of the undesirableor adverse symptoms and complications associated with a recall immuneresponse.

The doses or “sufficient amount” to achieve a therapeutic benefit orimprovement in a subject's condition are effective to alleviate orameliorate one, several or all adverse symptoms or complications of thecondition, to a measurable extent, although reducing, inhibiting orpreventing progression or a worsening of the condition or an adversesymptom, is a satisfactory outcome. The dose may be proportionallyincreased or reduced as indicated by the status of the disease beingtreated or the side effects of the treatment. Doses also consideredsufficient are those that result in a reduction of the use of anothertherapeutic regimen or protocol. For example, an OX40 or OX40L signalingantagonist is considered as having a therapeutic effect ifadministration of the antagonist results in reducing the frequency ordosage of a different treatment used to inhibit or reduce undesirable oradverse symptoms or complications of the condition.

As used herein, the term “signal” or “signaling,” when used in referenceto OX40 or OX40L, refers to an activity or function of OX40 or OX40L. Anexemplary biological function is mediating a recall response, e.g., aTh2 recall response. Signaling of OX40 or OX40L can be modulateddirectly, by increasing or decreasing an OX40 or OX40L activity orfunction; or indirectly, by altering expression of OX40 or OX40L, or byaltering expression or activity of another molecule(s) which in turnmodulates an OX40 or OX40L activity or function, or expression of OX40or OX40L.

Molecules that modulate OX40 or OX40L signaling include compounds thatbind to OX40 or OX40L such as small organic compounds (e.g., drugs),polypeptide sequences (e.g., OX40/OX40L antibodies), and modified formsof OX40/OX40L (e.g., soluble, variant, fusion, mimetic, or dominantnegative forms of OX40/OX40L). Molecules that modulate OX40 or OX40Lsignaling also include nucleic acid sequences. Molecules that modulateOX40 or OX40L signaling include compounds that modulate expression oractivity of another molecule(s) which in turn modulates an OX40 or OX40Lactivity or function, or expression of OX40 or OX40L.

“Antibodies” refer to mammalian, human, humanized or primatized forms ofheavy or light chain, V_(H) and V_(L), respectively, immunoglobulin (Ig)molecules. “Antibody” means any monoclonal or polyclonal immunoglobulinmolecule, such as IgM, IgG, IgA, IgE, IgD, and any subclass thereof. Theterm “antibody” includes intact immunoglobulin molecules, two fulllength heavy chains linked by disulfide bonds to two full length lightvariable domains, V_(H) and V_(L), individually or in any combination,as well as fragments of immunoglobulins, such as Fab, Fab′, (Fab′)₂, Fv,Fd, scFv and sdFv, unless otherwise expressly stated.

An OX40 or OX40L antibody means an antibody that specifically binds toOX40 or OX40L. As used herein, the term “bind” or “binding” means thatthe compositions referred to have affinity for each other. “Specificbinding” is where the binding is selective between two molecules. Thus,specific binding of an antibody for OX40 or OX40L is that which isselective for an epitope present in OX40 or OX40L. Typically, specificbinding can be distinguished from non-specific when the dissociationconstant (K_(D)) is less than about 1×10⁻⁵M or less than about 1×10⁻⁶Mor 1×10⁻⁷ M. Selective binding can be distinguished from non-selectivebinding using assays known in the art (e.g., Immunoprecipitation, ELISA,Western blotting) with appropriate controls.

Monoclonal antibodies are made by methods known in the art (Kohler etal., Nature, 256:495 (1975); and Harlow and Lane, Using Antibodies: ALaboratory Manual, Cold Spring Harbor Laboratory, 1999). Briefly,monoclonal antibodies can be obtained by injecting mice with antigen(for example, intact polypeptide or peptide fragments of OX40/OX40L).The polypeptide or peptide used to immunize an animal may be derivedfrom translated DNA or chemically synthesized and conjugated to acarrier protein. Commonly used carriers which are chemically coupled tothe immunizing peptide include, for example, keyhole limpet hemocyanin(KLH), thyroglobulin, bovine serum albumin (BSA), and tetanus toxoid.Antibody production is verified by analyzing a serum sample, removingthe spleen to obtain B lymphocytes, fusing the B lymphocytes withmyeloma cells to produce hybridomas, cloning the hybridomas, selectingpositive clones that produce antibodies to the antigen, and isolatingthe antibodies from hybridoma cultures. Monoclonal antibodies can beisolated and purified from hybridoma cultures by a variety ofestablished techniques which include, for example, affinitychromatography with Protein-A Sepharose, size-exclusion chromatography,and ion-exchange chromatography (see e.g., Coligan et al., CurrentProtocols in Immunology sections 2.7.1-2.7.12 and sections 2.9.1-2.9.3;and Barnes et al., “Methods in Molecular Biology,” 10:79-104, HumanaPress (1992)).

A “human antibody” means that the amino acid sequence of the antibody isfully human, i.e., human heavy and light chain variable and constantregions. The antibody amino acids are coded for in the human DNAantibody sequences or exist in a human antibody. An antibody that isnon-human may be made fully human by substituting non-human amino acidresidues with amino acid residues that exist in a human antibody. Aminoacid residues present in human antibodies, CDR region maps and humanantibody consensus residues are known in the art (see, e.g., Kabat,Sequences of Proteins of Immunological Interest, 4^(th) Ed. USDepartment of Health and Human Services. Public Health Service (1987);Chothia and Lesk, J. Mol. Biol. (1987) 186:651; Padlan Mol. Immunol.(1994) 31:169; and Padlan Mol. Immunol. (1991) 28:489). Methods ofproducing human antibodies are known in the art (see, for example, WO02/43478 and WO 02/092812).

The term “humanized,” when used in reference to an antibody, means thatthe antibody sequence has non-human amino acid residues of one or morecomplementarity determining regions (CDRs) that specifically bind to theantigen in an acceptor human immunoglobulin molecule, and one or morehuman amino acid residues in the Fv framework region (FR) that flank theCDRs. Any mouse, rat, guinea pig, goat, non-human primate (e.g., ape,chimpanzee, macaque, orangutan, etc.) or other animal antibody may beused as a CDR donor for producing humanized antibody. Human frameworkregion residues can be replaced with corresponding non-human residues.Residues in the human framework regions can therefore be substitutedwith a corresponding residue from the non-human CDR donor antibody. Ahumanized antibody may include residues, which are found neither in thehuman antibody nor in the donor CDR or framework sequences. The use ofantibody components derived from humanized monoclonal antibodies reducesproblems associated with the immunogenicity of non-human regions.Methods of producing humanized antibodies are known in the art (see, forexample, U.S. Pat. Nos. 5,225,539; 5,530,101, 5,565,332 and 5,585,089;Riechmann et al., (1988) Nature 332:323; EP 239,400; WO91/09967; EP592,106; EP 519,596; Padlan Molecular Immunol. (1991) 28:489; Studnickaet al., Protein Engineering (1994) 7:805; Singer et al., J. Immunol.(1993) 150:2844; and Roguska et al., Proc. Nat'l. Acad. Sci. USA (1994)91:969).

“Primatized” antibodies are within the meaning of “humanized” as usedherein, except that the acceptor human immunoglobulin molecule andframework region amino acid residues may be any primate residue (e.g.,chimpanzee, ape, orangutan, gibbon, etc.), in addition to any humanresidue.

A specific example of an OX-40 antibody is OX-40-specific monoclonalantibody OX-86 (al-Shamkhani et al., Eur J Immunol. (1996) 26:1695;Rogers and Croft, J Immunol. (2000) 164:2955; and Kjaergaard et al., JImmunol. (2001) 167:6669). Specific examples of OX-40- andOX40L-specific antagonist and agonist antibodies are also known in theart: antagonist anti-mouse OX40L antibody RM134L (Example 1 and Akiba etal., J. Immunol. (1999) 162:7058); antagonist anti-human OX40L (gp34)antibody ik-1 (Matsumura et al., J Immunol. (1999) 163:3007); antagonistanti-rat OX40L ATM-2 (Satake et al., Biochem Biophys Res Commun. (2000)270:1041) and agonistic anti-OX40 antibody (Pan et al., Mol Ther. (2002)6:528).

As used herein, the terms “peptide,” “polypeptide” and “protein” areused interchangeably and refer to two or more amino acids covalentlylinked by an amide bond or non-amide equivalent. Polypeptides includefull length native polypeptide, and “modified” forms such assubsequences, variant sequences, fusion/chimeric sequences anddominant-negative sequences. Specific non-limiting examples ofpolypeptides include antibodies and forms of OX40 and OX40L havingantagonistic and agonistic activity on OX40/OX40L signaling.

Peptides include L- and D-isomers, and combinations thereof. Peptidescan include modifications typically associated with post-translationalprocessing of proteins, for example, cyclization (e.g., disulfide oramide bond), phosphorylation, glycosylation, carboxylation,ubiquitination, myristylation, or lipidation. Modified peptides can haveone or more amino acid residues substituted with another residue, addedto the sequence or deleted from the sequence. Specific examples includeone or more amino acid substitutions, additions or deletions (e.g., 1-3,3-5, 5-10, 10-20, or more).

Subsequences and fragments refer to polypeptides having one or morefewer amino acids in comparison to a reference (e.g., native)polypeptide sequence. A recombinant soluble OX40 subsequence can haveagonist activity (Kotani et al., Immunol Lett. 2002 84:1) or antagonistactivity. An antibody subsequence that specifically binds to OX40 orOX40L can retain at least a part of its binding or agonist or antagonistfunction.

A variant peptide can have a sequence with 50%, 60%, 70%, 75%, 80%, 85%,90%, 95%, 96%, 97%, 98%, or more identity to a reference sequence (e.g.,OX40/OX40L or an antibody that binds to OX40/OX40L). Variant sequencesinclude naturally occurring alterations of sequence, due tointra-species polymorphisms or different species, as well asartificially produced alterations of sequence. Sequence homology betweenspecies is in the range of about 70-80%. An amino acid substitution isone example of a variant.

A “conservative substitution” is the replacement of one amino acid by abiologically, chemically or structurally similar residue. Biologicallysimilar means that the substitution is compatible with an activity orfunction of the unsubstituted sequence. Structurally similar means thatthe amino acids have side chains with similar length, such as alanine,glycine and serine, or having similar size. Chemical similarity meansthat the residues have the same charge or are both hydrophilic orhydrophobic. Particular examples include the substitution of onehydrophobic residue, such as isoleucine, valine, leucine or methioninefor another, or the substitution of one polar residue for another, suchas the substitution of arginine for lysine, glutamic for aspartic acids,or glutamine for asparagine, serine for threonine, and the like.

Peptides synthesized and expressed as fusion proteins have one or moreadditional domains linked thereto, and are also referred to as chimericpolypeptides. The additional domain(s) may confer an additional functionupon the sequence. For example, OX40-IgG fusion proteins can haveantagonistic activity (Taylor et al., J Leukoc Biol. (2002) 72:522) oragonist activity.

The term “fusion,” when used in reference to two or more molecules(e.g., polypeptides) means that the molecules are covalently attached. Aparticular example for attachment of two protein sequences is an amidebond or equivalent. The term “chimeric,” and grammatical variationsthereof, when used in reference to a protein, means that the protein iscomprised of one or more heterologous amino acid residues from one ormore different proteins.

The term “heterologous,” when used in reference to a polypeptide, meansthat the polypeptide is not normally contiguous with the otherpolypeptide in its natural environment. Thus, a chimeric polypeptidemeans that a portion of the polypeptide does not exist fused with theother polypeptide in normal cells. In other words, a chimericpolypeptide is a molecule that does not normally exist in nature, i.e.,such a molecule is produced by the hand man, e.g., artificially producedthrough recombinant DNA technology.

As used herein, the term “mimetic” refers to a synthetic chemicalcompound which has substantially the same structural and/or functionalcharacteristics as the reference molecule. The mimetic can be entirelycomposed of synthetic, non-natural amino acid analogues, or can be achimeric molecule including one or more natural peptide amino acids andone or more non-natural amino acid analogs. The mimetic can alsoincorporate any number of natural amino acid conservative substitutionsas long as such substitutions do not destroy activity. As withpolypeptides which are conservative variants, routine testing can beused to determine whether a mimetic modulates OX40/OX40L signaling.

Peptide mimetics can contain any combination of non-natural structuralcomponents, which are typically from three structural groups: a) residuelinkage groups other than the natural amide bond (“peptide bond”)linkages; b) non-natural residues in place of naturally occurring aminoacid residues; or c) residues which induce secondary structural mimicry,i.e., induce or stabilize a secondary structure, e.g., a beta turn,gamma turn, beta sheet, alpha helix conformation, and the like. Forexample, a polypeptide can be characterized as a mimetic when one ormore of the residues are joined by chemical means other than an, amidebond. Individual peptidomimetic residues can be joined by amide bonds,non-natural and non-amide chemical bonds other chemical bonds orcoupling means including, for example, glutaraldehyde,N-hydroxysuccinimide esters, bifunctional maleimides,N,N′-dicyclohexylcarbodiimide (DCC) or N,N′-diisopropylcarbodiimide(DIC). Linking groups alternative to the amide bond include, forexample, ketomethylene (e.g., —C(═O)—CH₂— for —C(═O)—NH—),aminomethylene (CH₂—NH), ethylene, olefin (CH═CH), ether (CH₂—O),thioether (CH₂—S), tetrazole (CN₄—), thiazole, retroamide, thioamide, orester (see, e.g., Spatola (1983) in Chemistry and Biochemistry of AminoAcids, Peptides and Proteins, Vol. 7, pp 267-357, “Peptide and BackboneModifications,” Marcel Decker, N.Y.).

Peptides and peptidomimetics can be produced and isolated using avariety of methods known in the art. Full length peptides and fragments(subsequences) can be synthesized using chemical methods known in theart (see, e.g., Caruthers, Nucleic Acids Res. Symp. Ser. (1980) 215;Horn, Nucleic Acids Res. Symp. Ser. (1980) 225; and Banga, A. K.,Therapeutic Peptides and Proteins, Formulation, Processing and DeliverySystems (1995) Technomic Publishing Co., Lancaster, Pa.), Peptidesynthesis can be performed using various solid-phase techniques (see,e.g., Roberge, Science (1995) 269:202; Merrifield, Methods Enzymol.(1997) 289:3). Automated synthesis may be achieved, e.g., using the ABI431A Peptide Synthesizer (Perkin Elmer) in accordance with themanufacturer's instructions.

Individual synthetic residues and polypeptides incorporating mimeticscan be synthesized using a variety of procedures and methodologies knownin the art (see, e.g., Organic Syntheses Collective Volumes, Gilman, etal. (Eds) John Wiley & Sons, Inc., NY). Peptides and peptide mimeticscan also be synthesized using combinatorial methodologies. Techniquesfor generating peptide and peptidomimetic libraries are known, andinclude, for example, multipin, tea bag, and split-couple-mix techniques(see, for example, al-Obeidi, Mol. Biotechnol. (1998) 9:205; Hruby,Curr. Opin. Chem. Biol. (1997) 1:114; Ostergaard, Mol. Divers. (1997)3:17; and Ostresh, Methods Enzymol. (1996) 267:220). Modified peptidescan be further produced by chemical modification methods (see, e.g.,Belousov, Nucleic Acids Res. (1997) 25:3440; Frenkel, Free Radic. Biol.Med. (1995) 19:373; and Blommers, Biochemistry (1994) 33:7886).

OX40/OX40L nucleic acids including antisense and RNAi can modulateexpression of OX40/OX40L. Antisense includes single, double or triplestranded polynucleotides and peptide nucleic acids (PNAs) that bind RNAtranscript or DNA. For example, a single stranded nucleic acid cantarget OX40 or OX40L transcript (e.g., mRNA). Oligonucleotides derivedfrom the transcription initiation site of the gene, e.g., betweenpositions −10 and +10 from the start site, are a particular one example.Triplex forming antisense can bind to double strand DNA therebyinhibiting transcription of the gene. “RNAi” is the use of doublestranded RNA sequences for inhibiting gene expression (see, e.g.,Kennerdell et al., (1998) Cell 95:1017; and Fire et al., (1998) Nature,391:806). Double stranded RNA sequences from an OX40 or OX40L codingregion may therefore be used to inhibit or prevent OX40 or OX40Lexpression.

Antisense and RNAi can be produced based upon the OX40 and OX40Lsequences known in the art. OX40 sequences are described, for example,in Latza et al. (Eur J Immunol. (1994) 24:677, human OX40), andBirkeland et al. (Eur J Immunol. (1995) 25:926, mouse OX40). OX40Lsequences are described, for example, in Godfrey et al. (J Exp Med.(1994) 180:757, human OX-40L), Baum et al. (EMBO J. (1994) 13:3992,mouse OX40L), and Akiba et al. (Biochem Biophys Res Commun. (1998)251:131, rat OX40L).

Molecules that directly or indirectly modulate expression of OX40/OX40Lfurther include cytokines such as include IL-10, which reducesOX40/OX40L signaling, and IL-1 and IL-4, which induce expression of OX40on T cells (Nakae et al. J Immunol. (2001) 167:90; and Iwakura Y,Cytokine Growth Factor Rev. (2002) August-October; 13(4-5):341). CD28also induces OX40 expression. CD40 and Toll-like receptor (TLR) agonistsincrease OX40L expression. Thus, molecules that can be employed in orderto reduce or inhibit OX40/OX40L signaling in accordance with theinvention include IL-10, and molecules that inhibit IL-4, CD28, CD40,TLR expression or activity (e.g., antibodies or antagonists that bindIL-4, CD28, CD40, or TLR).

Dominant negative molecules that can directly or indirectly modulateOX40/OX40L signaling include dominant negative TRAF (tumor necrosisfactor receptor (TNFR) associated factors) family members, Akt (ProteinKinase B), JNK (Jun N-terminal Kinase), and IKK (I kappa B Kinase)molecules (Kawamata et al., J. Biol. Chem (1998) 273:5608; Kelly et al.,J. Immunol. (2002) 168:597; Rincon et al., J. Exp. Med. (1998) 188:1817;and Harhaj and Sun, J. Biol. Chem. (1998) 273:25185).

Excluded agents from the methods of the invention are agents that areknown in the art and that function to reduce or inhibit a recall immuneresponse (e.g., Th2 recall response) by inhibiting OX40/OX40L signaling,and that have been used for that purpose. Thus, agents known in the artand that have been used to treat a recall immune response associatedwith allergic asthma, for example, if they function by reducing,inhibiting or preventing OX40/OX40L signaling, are excluded from theinvention in vitro, ex vivo or in vivo methods.

Agents that may be excluded include one or more of the following:budesonide, prednisone, flunisolide, flunisolide hydrofluoroalkane,estrogen, progesterone, dexamethasone, loteprednol, bambuterol,formoterol, salmeterol, albuterol, ipratropium bromide, oxitropiumbromide, cromolyn, terfenadine, astemizole, hydroxyzine,chlorpheniramine, tripelennamine, cetirizine, desloratadine,mizolastine, fexofenadine, olopatadine hydrochloride, norastemizole,levocetirizine, levocabastine, azelastine, ebastine, loratadine,oxatomide, montelukast, zafirlukast, zileuton, ibudilast, cilomilast,BAY 19-8004, theophylline, doxofylline, seratrodast, ozagrelhydrochloride, ramatroban, celecoxib and rofecoxib.

Invention methods include treatment protocols and therapeutic regimensor strategies alone, and in combination with each other. For example,any treatment protocol or therapeutic regimen or strategy that inhibits,reduces or prevents a recall response, or reduces the likelihood that arecall response will occur, can be used to reduce or inhibit a recallimmune response alone, or in combination with another treatment protocolor therapeutic regimen. Such treatments include compounds, agents,therapies and treatments having an immune-inhibiting or immune-reducingactivity or function. The term “immune-response inhibiting,” or“immune-response reducing” when used in reference to such a compound,agent, therapy or treatment, means that the compound, agent, therapy ortreatment decreases, prevents, an immune response that is humoral orcell-mediated.

Particular non-limiting examples of agents useful for treatinginflammation (e.g., asthma) include immunosuppressive agents such ascorticosteroids (steroid receptor agonists) including budesonide,prednisone, flunisolide, flunisolide hydrofluoroalkane, estrogen,progesterone, dexamethasone and loteprednol; beta-agonists (e.g., shortor long-acting) such as bambuterol, formoterol, salmeterol, albuterol;anticholinergics such as ipratropium bromide, oxitropium bromide,cromolyn and calcium-channel blocking agents; antihistamines such asterfenadine, astemizole, hydroxyzine, chlorpheniramine, tripelennamine,cetirizine, desloratadine, mizolastine, fexofenadine, olopatadinehydrochloride, norastemizole, levocetirizine, levocabastine, azelastine,ebastine and loratadine; antileukotrienes (e.g., anti-cysteinylleukotrienes (CysLTs)) such as oxatomide, montelukast, zafirlukast andzileuton; phosphodiesterase inhibitors (e.g., PDE4 subtype) such asibudilast, cilomilast, BAY 19-8004, theophylline (e.g.,sustained-release) and other xanthine derivatives (e.g., doxofylline);thromboxane antagonists such as seratrodast, ozagrel hydrochloride andramatroban; prostaglandin antagonists such as COX-1 and COX-2 inhibitors(e.g., celecoxib and rofecoxib), aspirin; and potassium channel openers.

Additional specific examples of anti-inflammatory agents includeantibodies, receptors or receptor ligands, such as anti-IgE (e.g.,rhuMAb-E25 omalizumab), -IgA and -IgG antibodies; antibodies and solublereceptors against cytokines such as IL-1, IL-4, IL-5, IL-9, IL-13 andIL-16 or growth factors such as granulocyte/macrophagecolony-stimulating factor; cytokines such as IL-10; mucolytics(depolymerize polymers of mucin or DNA/actin, or increase coughclearance) such as ambroxol and N-acetylcysteine; expectorants; andallergens (allergan immunotherapy).

Treatment strategies include avoidance of triggers (environmental orfood allergan avoidance) and self-management.

Invention methods include applications in vitro, ex vivo and in vivo,i.e., in a subject. The term “subject,” also referred to as “patient,”as used herein means an animal, such as a non-mammal or mammalian (e.g.,primate, human) organism. Subjects further include animal models inwhich a recall immune response is directly or indirectly involved in anundesirable or adverse symptom or physiological or psychologicalcomplication or condition.

Candidate subjects and patients include any subject having or at risk ofhaving a recall response. Specific examples include subjects with ahistory of having an undesirable or adverse recall response, or anundesirable or adverse symptom or physiological or psychologicalcomplication or condition associated or caused by a recall response.Another example is a subject who has not been diagnosed with anundesirable or adverse recall response, or complication associated orcaused by a recall response, but who is suspected of having a recallresponse. For example, a subject may be suspected of having asthma, buthas not yet been diagnosed with asthma. Such subjects, suspected ofhaving a recall response, are appropriate candidate subjects. Additionalspecific non-limiting examples are described herein, such as acute orchronic asthma (e.g., allergic), and are also known in the art.

Agents and compounds useful in the methods of the invention can beformulated into a pharmaceutically acceptable carrier or diluent usingknown techniques. The pharmaceutically acceptable carrier or diluent canbe selected based upon the amount of active ingredient with which it isto be combined, the route of administration and other known variables.

Pharmaceutical compositions include “pharmaceutically acceptable” and“physiologically acceptable” carriers, diluents or excipients. The terms“pharmaceutically acceptable” and “physiologically acceptable,” whenreferring to carriers, diluents or excipients includes solvents (aqueousor non-aqueous), detergents, solutions, emulsions, dispersion media,coatings, isotonic and absorption promoting or delaying agents,compatible with pharmaceutical administration and with the othercomponents of the formulation. Such formulations further include atablet (coated or uncoated), capsule (hard or soft), microbead,emulsion, powder, granule, crystal, suspension, syrup or elixir.

Pharmaceutical compositions can be formulated to be compatible with aparticular route of administration. Compositions for parenteral,intradermal, or subcutaneous administration can include a sterilediluent, such as water, saline solution, fixed oils, polyethyleneglycols, glycerine, propylene glycol or other synthetic solvents. Thepreparation may contain one or more preservatives to preventmicroorganism growth (e.g., antibacterial agents such as benzyl alcoholor methyl parabens; antioxidants such as ascorbic acid or sodiumbisulfite; chelating agents such as ethylenediaminetetraacetic acid;buffers such as acetates, citrates or phosphates and agents for theadjustment of tonicity such as sodium chloride or dextrose).

Pharmaceutical compositions for injection include sterile aqueoussolutions (where water soluble) or dispersions and sterile powders forthe extemporaneous preparation of sterile injectable solutions ordispersion. For intravenous administration, suitable carriers includephysiological saline, bacteriostatic water, Cremophor EL™ (BASF,Parsippany, N.J.) or phosphate buffered saline (PBS). The carrier can bea solvent or dispersion medium containing, for example, water, ethanol,polyol (e.g., glycerol, propylene glycol, and polyetheylene glycol), andsuitable mixtures thereof. Antibacterial and antifungal agents include,for example, parabens, chlorobutanol, phenol, ascorbic acid andthimerosal. Including an agent that delays absorption, for example,aluminum monostearate and gelatin can prolong absorption of injectablecompositions.

For transmucosal or transdermal administration, penetrants appropriateto the barrier to be permeated are used in the formulation. Suchpenetrants are known in the art, and include, for example, fortransmucosal administration, detergents, bile salts, and fusidic acidderivatives; for transdermal administration, ointments, salves, gels, orcreams. Transdermal delivery can also be achieved using patches.

Additional pharmaceutical formulations and delivery systems are known inthe art and are applicable in the methods of the invention (see, e.g.,Remington: The Science and Practice of Pharmacy, 20^(th) ed.,Lippincott, Williams & Wilkins (2000); Ansel at al., PharmaceuticalDosage Forms and Drug Delivery Systems, 7^(th) ed., Lippincott Williams& Wilkins Publishers (1999); Kibbe (ed.), Handbook of PharmaceuticalExcipients American Pharmaceutical Association, 3^(rd) ed. (2000);Pharmaceutical Principles of Solid Dosage Forms, Technonic PublishingCo., Inc., Lancaster, Pa., (1993); and Poznansky et al., Drug DeliverySystems, R. L. Juliano, ed., Oxford, N.Y. (1980), pp. 253-315)

The methods of the invention include administering as a single ormultiple dose each day (e.g., at a low dose), or intermittently (e.g.,every other day, once a week, etc., optionally at a higher dose).Methods further include prohylactic delivery in order to reduce onset ofa recall response.

Delivery routes or routes of administration include local, regional, andsystemic in accordance with any protocol or route that achieves thedesired effect. Administration can be achieved via inhalation (e.g.,intra-tracheal), orally, intravenously, intraarterially,intravascularly, intrathecally, intraperitonealy, intramuscularly,subcutaneously, intracavity, transdermally (e.g., topical),transmucosally (e.g., buccal or nasal), by sustained release (e.g.,gradual perfusion over time), as multiple doses or a single bolus. Localtreatment methods also include oral or sublingual delivery.

A particular example is inhalation or intranasal administration, whichprovides bronchial or nasal delivery. The formulation can beadministered in the form of an aerosol or mist. For aerosoladministration, the formulation can be supplied in finely divided formalong with a surfactant and propellant. The device for delivering theformulation to respiratory tissue can be in a formulation thatvaporizes. Additional delivery systems known in the art include drypowder aerosols, liquid delivery systems, inhalers, air jet nebulizersand propellant systems (see, e.g., Patton (1998) Biotechniques 16:141;Sayani (1996) Crit. Rev. Ther. Drug Carrier Syst. 13:85; DuraPharmaceuticals, San Diego, Calif.; Aradigm, Hayward, Calif.; Aerogen,Santa Clara, Calif.; and Inhale Therapeutic Systems, San Carlos,Calif.). The agent or compound that inhibits or reduces OX40 or OX40Lsignaling, expression or activity can therefore be formulated into anaerosol or non-aerosol.

Methods of identifying (screening) agents that reduce or inhibit OX40 orOX40L signaling, expression or activity are provided. In one embodiment,a method includes providing a test agent that reduces or inhibitssignaling, expression or activity of OX40 or OX40 ligand (OX40L); andmeasuring a recall immune response in the presence of the test agent. Inanother embodiment, a method includes providing a test agent that bindsto OX40 or OX40 ligand (OX40L); and measuring a recall immune responsein the presence of the test agent. A reduction or inhibition of a recallresponse identifies the test agent as an agent that reduces or inhibitsa recall immune response.

Methods of identifying (screening) agents that alleviate or ameliorate asymptom associated with a secondary or subsequent immune response to anantigen are also provided. In one embodiment, a method includesproviding a test agent that reduces or inhibits signaling, expression oractivity of OX40 or OX40 ligand (OX40L); and measuring a symptomassociated with a secondary or subsequent immune response to an antigenin the presence of the test agent. In another embodiment, a methodincludes providing a test agent that binds to OX40 or OX40 ligand(OX40L); and measuring a symptom associated with a secondary orsubsequent immune response to an antigen in the presence of the testagent. A reduction or inhibition of a symptom associated with asecondary or subsequent immune response to an antigen identifies thetest agent as an agent that alleviates or ameliorates a symptomassociated with a secondary or subsequent immune response to an antigen.

In one aspect of identifying (screening) an agent, the recall immuneresponse is mediated at least in part by OX40/OX40L signaling. Inadditional aspects, the test agent includes an antibody (e.g., human orhumanized), a modified OX40 or OX40L (e.g., sequence variant,subsequence, chimera or dominant negative form), an antisense nucleicacid molecule or RNAi that binds to OX40 or OX40L DNA or RNA, or acytokine. Agents can be identified (screened) by detecting changes in arecall immune response or a symptom associated with a recall immuneresponse in vivo (e.g., in a mammal). Exemplary symptoms are those setforth herein and known in the art and include, for example, swelling,enlargement, mucus production, rash, eosinophil infiltration, leukocyteor lymphocyte infiltration, cytokine or chemokine production,hyperplasia, inflammatory lesions or necrosis.

Methods of identifying (screening) agents that alleviate or ameliorate asymptom associated with asthma, for example, allergic asthma, areadditionally provided. In one embodiment, a method includes providing atest agent that reduces or inhibits signaling, expression or activity ofOX40 or OX40 ligand (OX40L); and measuring a symptom associated withasthma in the presence of the test agent. In another embodiment, amethod includes providing a test agent that binds to OX40 or OX40 ligand(OX40L); and measuring a symptom associated with asthma in the presenceof the test agent. A reduction or inhibition of a symptom associatedwith asthma identifies the test agent as an agent that alleviates orameliorates a symptom associated with asthma.

Methods of identifying (screening) agents that alleviate or ameliorate asymptom associated with asthma, for example, allergic asthma, arefurther provided. In one embodiment, a method includes providing a testagent that reduces or inhibits signaling, expression or activity of OX40or OX40 ligand (OX40L); and measuring asthma in the presence of the testagent. In another embodiment, a method includes providing a test agentthat binds to OX40 or OX40 ligand (OX40L); and measuring asthma in thepresence of the test agent. Alleviating or ameliorating asthmaidentifies the test agent as an agent for treating asthma.

In one aspect of identifying (screening) an agent, the asthma ismediated at least in part by OX40/OX40L signaling. In additionalaspects, the test agent includes an antibody (e.g., human or humanized),a modified OX40 or OX40L (e.g., sequence variant, subsequence, chimeraor dominant negative form), an antisense nucleic acid molecule or RNAithat binds to OX40 or OX40L DNA or RNA, or a cytokine. Agents can beidentified (screened) by detecting a change in an undesirable or adversesymptom or complication associated with asthma in vivo (e.g., in amammal). Exemplary symptoms are those set forth herein and known in theart and include, for example, swelling, enlargement, mucus production,eosinophil infiltration (e.g., of lung), leukocyte or lymphocyteinfiltration (e.g., of lung), cytokine or chemokine production (e.g.,Th2 cytokine production), hyperplasia (e.g., of goblet cell or mucussecreting epithelium), inflammatory lesions or necrosis (e.g., of lung),wheezing, shortness of breath, chest tightness, cough, and sputumproduction, airflow restriction, airway edema or mucus production.

Kits that include one or more agents that reduce or inhibit or preventOX40 or OX40L signaling, expression or activity, packaged into suitablepackaging material, are also provided. A kit typically includes a labelor packaging insert including a description of the components orinstructions for use in vitro, in vivo, or ex vivo, of the componentstherein. A kit can contain a collection of such components.

In one embodiment, a kit includes an agent sufficient to reduce orinhibit or prevent OX40 or OX40L signaling, expression or activity andinstructions for treating a recall immune response. In anotherembodiment, the container includes two or more such agents. In yetanother embodiment, the kit or container includes an immune-responseinhibiting or immune-response reducing agent.

The term “packaging material” refers to a physical structure housing thecomponents of the kit. The packaging material can maintain thecomponents sterilely, and can be made of material commonly used for suchpurposes (e.g., paper, corrugated fiber, glass, plastic, foil, ampules,etc.). The label or packaging insert can include appropriate writteninstructions.

Kits of the invention therefore can additionally include labels orinstructions for using the kit components in a method of the invention.Instructions can include instructions for practicing any of the methodsof the invention described herein including treatment methods. Thus, forexample, a kit can include one or more agents that inhibit or reduce orprevent OX40 or OX40L signaling, expression or activity, together withinstructions for administering to a subject in a treatment method of theinvention.

The kit components (e.g., agents) can be packaged in unit dosage formfor ease of administration and uniformity of dosage. “Unit dosage form”refers to physically discrete unitary dosages for administration to thesubject to be treated; each unit contains a predetermined quantity ofcompound that produces a desired effect, optionally in combination witha pharmaceutical carrier or excipient.

The instructions may be on “printed matter,” e.g., on paper or cardboardwithin or affixed to the kit, or on a label affixed to the kit orpackaging material, or attached to a vial or tube containing a componentof the kit. Instructions may additionally be included on a computerreadable medium, such as a disk (floppy diskette or hard disk), opticalCD such as CD- or DVD-ROM/RAM, magnetic tape, electrical storage mediasuch as RAM and ROM and hybrids of these such as magnetic/opticalstorage media.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention pertains. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the present invention, suitable methods andmaterials are described herein.

All publications, patents and other references cited herein areincorporated by reference in their entirety. In case of conflict, thespecification, including definitions, controls.

As used herein, the forms “a”, “and,” and singular “the” include pluralreferents unless the context clearly indicates otherwise. Thus, forexample, reference to an “agent” or an “antibody” includes a pluralityof agents and antibodies, and reference to “a symptom” includesreference to one or more symptoms.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, the following examples are intended to illustrate but notlimit the scope of invention described in the claims.

EXAMPLES Example 1

This example describes various materials and methods.

Mice

The studies conform to the principles outlined by the animal Welfare Actand the National Institutes of Health guidelines for the care and use ofanimals in biomedical research, Female C57BL/6 mice (6-8 week old) werepurchased from Jackson Labs (Bar Harbor, Me.). OT-II TCR transgenic mice(Barnden et al., Immunol Cell Biol. (1998) 76:34), were used as a sourceof Vβ5/Vα2 CD4+ T cells responsive to peptide 323-339 of ovalbumin(OVA). OX40-deficient OT-II TCR transgenic mice were generated bycrossing OT-II mice with OX40−/− mice.

Induction of Allergic Airway Inflammation

The protocol for induction of pulmonary inflammation via antigensensitization and aerosol challenge was as described previously (Jemberet al., J Exp Med. (2001) 193:387). Briefly, groups of 4 C57BL/6 micewere sensitized by intraperitoneal (i.p.) injection of 20 μg OVA protein(chicken egg albumin; Sigma-Aldrich), adsorbed to 2 mg aluminumhydroxide (Alum; Pierce) in phosphate buffered saline (PBS) on day 0.Unsensitized (naïve) mice received 2 mg Alum in PBS. On day 25 or later,mice were challenged via the airways with OVA (5 mg/ml in 15 ml of PBS)for 30 min, once a day for four consecutive days, by ultrasonicnebulization (Jember et al., (2001), supra). To block OX40-OX40Linteraction, mice were injected i.p. with 200 μg of rat anti-mouse-OX40Lblocking mAb (RM134L, rat IgG2bκ; Akiba et al., J Immunol, (1999)162:7058) or isotype control antibody (IgG2b); given on the indicateddays in PBS, 30 min prior to OVA challenge.

Analysis of the Asthma Phenotype

Airway responsiveness (AHR) was measured in vivo 1-3 hr after the lastaerosolized OVA exposure by recording respiratory curves by whole-bodyplethysmography (Buxco Technologies) in response to inhaled methacholine(MCh; 1.25-10 mg/ml; Aldrich chemical) as described (Jember et al.,(2001), supra). Bronchoalveolar lavage (BAL) cytology, lunghistopathology, OVA-specific and total IgE and lung cytokine profilesobtained by ELISA were determined as described (Jember et al., (2001),supra). All data unless otherwise indicated were collected 24 h afterthe final antigen challenge.

Stimulation of Lung, Peribronchial Lymph Node, and Spleen Cells In Vitro

Peribronchial lymph nodes (PBLNs) and spleens were collected at the timeof lung harvest. Lavaged lungs were digested with Hanks' balanced saltsolution (HBSS; Gibco) supplemented with 3 mg/ml collagenase (Type V;Boehringer Mannheim), 0.1 mg/ml Dnase (Sigma), 100 μg/ml streptomycin(Invitrogen), and 100 μml penicillin (Invitrogen) for 60 min at 37° C.After lysing red blood cells (RBCs) with ACK lysis buffer, PBLN, spleenand lung cells were resuspended in RPMI-1640 medium (Gibco) supplementedwith 10% FCS (Omega Scientific), 1% L-glutamine (Invitrogen), 100 μg/mlstreptomycin, 100 U/ml penicillin and 50 μM 2-mercaptoethanol (Sigma).Splenocytes (2×10⁵ cells/well), lung cells (8×10⁵ cells/well), or PBLNscells (2×10⁵ cells/well) were plated in round-bottomed 96-wellmicrotiter plates in 200 μl with increasing concentrations of OVA(10-100 μg/ml) for 72 hrs at 37° C. After 56 hr, 1 μCi of3^(H)-thymidine (ICN Biomedicals) was added to each well. The cells wereharvested 16 hr later, and thymidine incorporation measured using aBetaplate scintillation counter. Each in vitro stimulation was performedin quadruplicate. Supernatants were harvested after 40 hr for cytokineanalysis.

Generation and Adoptive Transfer of OVA-Specific Th2 Cells

Lymph node and spleen cells from wild-type (OX40+/+) OT-II mice or OT-IIOX40-deficient (OX40−/−) mice were pooled and CD4 cells isolated aspreviously described (Gramaglia et al., J Immunol. (1998) 161:6510). Thepurity of CD4+ T cells was confirmed to be >98% by FACS analysis. Togenerate memory Th2 cells, naïve T cells (1×10⁶ cells/ml) were culturedin two ways: with plate-bound αCD3 (3 μg/ml) and soluble αCD28 (10μg/ml), or with 2×10⁶/ml syngeneic splenic APCs and 0.1 μM OVA peptide,plus IL-2 (5 ng/ml), IL-4 (20 ng/ml), αIFN-γ (10 μg/ml), and αIL-12 (10μg/ml), for 3 days at 37° C. At the end of this culture, cells wereremoved, washed, and then cultured for another 3-6 d without furtherstimulation.

In some cases, primed T cells were labeled with CFSE (5- and6-carboxyfluorescein diacetate succinimidly ester C-1157; MolecularProbes, Eugene, Oreg.) and 2×10⁶ were injected into the tail vein ofnaïve C57BL/6 mice in 200 μl. One day after transfer of cells, mice werechallenged with inhaled OVA (5 mg/ml in 15 ml PBS) for 30 min daily for2 consecutive days. Animals were sacrificed for analyses 1 day later.Control mice received inhaled PBS only. In vivo cell division and T cellaccumulation were assessed by tracking transferred T cells with flowcytometry based on co-expression of CFSE and Vα2.

Following the primary culture, an aliquot of primed T cells wereretained to determine proliferation, survival, and cytokine productionin recall responses in vitro. 5×10⁵ CD4 T cells/ml were recultured with2×10⁶/ml syngeneic splenic APCs and OVA peptide. IL-4, IL-5, IL-13, andIFN-γ levels from cell supernatants were determined by ELISA at 40 hr.Proliferation was measured in triplicate by the incorporation of³H-thymidine (1 μCi/well; ICN Pharmaceuticals) during the last 12 hr ofculture. T cell survival was determined by trypan blue exclusion.

Flow Cytometry Analysis

Cells were stained with FITC-conjugated anti-CD4, PE-conjugatedanti-OX40, Cychrome-conjugated anti-CD44, or PE-conjugated anti-Vα2 at4° C. for 30 min. Immunostained cells were analyzed on a FACScan flowcytometer (Becton Dickenson) using CELLQest software.

Example 2

This example describes data indicating that OX40 is expressed on memoryTh2 cells.

To determine if memory CD4 cells express OX40, C57BL/6 mice wereimmunized i.p. with OVA adsorbed to alum (FIGS. 1A. and 1B, primed).Twenty-five days later mice were challenged by inhalation of nebulizedOVA on 4 consecutive days (FIGS. 1A. and 1B, primed/challenged). T cellsfrom mice primed 4 weeks prior with OVA in alum were stained.

A significant number of CD44hi memory CD4 cells in lymph nodes thatexpressed OX40 at low/moderate levels were visualized. In contrast,CD44lo naïve CD4 cells did not express OX40 without antigen exposure(FIG. 1A), as shown previously (Gramaglia et al., (1998) J Immunol.161:6510). Unimmunized mice also contained a proportion of CD44hi CD4cells that expressed OX40 at low levels suggesting that OX40 can bereadily available to some memory T cells. OX40 levels were upregulatedon responding CD44hi memory T cells in lung draining lymph nodes afterchallenge with aerosolized antigen (FIG. 1A); the absolute number ofOX40 positive CD44hi CD4 cells (mean of 4 mice) increased markedly (FIG.1C, and see below).

This large increase in OX40-expressing CD44hi cells was not observed inunprimed mice challenged with aerosolized antigen. Thus, these resultsdirectly indicate a memory T cell response and accumulation of memoryeffector cells.

Few CD4 cells were present in the lungs of primed but unchallenged mice,and OX40 was not detected on either CD44hi or lo cells (FIG. 1B).However, after antigen challenge a large number of OX40-expressingCD4/CD44hi cells were present in the lung (FIG. 1B).

These data indicate that OX40 is expressed on memory/memory effector Tcells and is available to play a role in the secondary response thatoccurs after re-encounter with antigen.

Example 3

This example describes data indicating that preventing OX40/OX40Linteraction impairs development of airway hyperreactivity andeosinophilia.

Characteristic features of allergic asthma are produced in micesensitized with OVA that are subsequently challenged later by OVAinhalation (Wills-Karp, M. Annu Rev Immunol. (1999) 17:255, Jember etal., (2001), supra). To examine the contribution of OX40/OX40Linteractions to lung inflammation, a blocking anti-OX40L mAb wasadministered to OVA-sensitized mice at the time of re-challenge withaerosolized antigen (FIG. 2A). In brief, unprimed control mice wereinjected i.p. with alum alone, while primed mice were sensitized withOVA adsorbed to alum. Twenty-five days later, all mice were challengedwith aerosolized OVA on 4 consecutive days (days 25-28), Either PBS(Group A: Alum/OVA), or control IgG (Group B: Alum-OVA/IgG-OVA) oranti-OX40L (Group C: Alum-OVA/RM134L-OVA) were administered i.p. on eachchallenge day. 1-3 hr after the last challenge, individual mice wereassessed for AHR.

OVA-immunized mice treated with isotype control antibody developed AHR.In contrast, administration of anti-OX40L dramatically reduced thedegree of AHR (FIG. 2B). Sensitized mice treated with control Ab duringaerosol challenge (Alum-OVA/IgG-OVA) responded with an increase in thetotal number of cells in BAL (FIG. 2C), which was evident as early as 48hrs and was mostly eosinophils (FIG. 2D). In striking contrast,administration of anti-OX40L during the challenge period(Alum-OVA/RM134L-OVA) virtually eliminated the increase in totalleukocytes (FIG. 2C) and eosinophils (FIG. 2D).

No cell infiltration was seen in unprimed but challenged animals. Thus,these results directly demonstrate that OX40/OX40L interactions mediaterecall response.

Example 4

This example describes data indicating that blocking OX40/OX40Linteractions inhibits development of airway tissue eosinophilia,goblet-cell hyperplasia, and mucus production.

To confirm the findings from lung lavages, lung sections werehistologically evaluated. In brief, groups of mice were immunized andchallenged as described in Example 3. 24 hr after the final OVA aerosolchallenge, lung tissue was stained with H&E (×100) for quantitation ofinflammatory infiltrates (FIG. 3A) and periodic acid-Schiff (PAS, ×200;purple-red staining) to highlight the mucus-secreting cells (FIG. 38),in sensitized and challenged animals receiving control Ig or anti-OX40L.Sections were graded for inflammation severity (FIG. 3A) and mucusproduction (FIG. 3B).

Mice receiving control antibody developed inflammatory lesions,characterized by a predominance of eosinophils and lymphocytes, andhyperplasia of mucus-secreting bronchial epithelial cells (FIG. 3A). Incontrast, lungs from anti-OX40L treated animals exhibited almost normalbronchial epithelium, and few infiltrating cells around the bronchiolesand blood vessels. Although many PAS⁺ (mucus-secreting) cells weredetected in the airway of mice sensitized and challenged that receivedthe control Ab, treatment with anti-OX40L markedly reduced the number ofPAS⁺ cells (FIG. 3B).

These results indicate that blocking OX40/OX40L interactions inhibitsdevelopment of airway tissue eosinophilia, goblet cell hyperplasia, andmucus production.

Example 5

This example describes data indicating that allergen-induced IgE and Th2cytokine production are reduced in anti-OX40L treated mice.

As an indirect test of whether OX40 signals were controlling memory Th2response contributing to the asthmatic reaction, Il-4, IL-5, IL-9 andIL-13 cytokine levels in the BAL, and production of the Th2-associatedantibody IgE, were measured in serum 24 hr after the final OVA aerosolchallenge (Example 4).

Treatment with anti-OX40L prevented the increase in IgE resulting fromthe recall response (FIG. 3C) as well as all Th2 cytokines (FIG. 3D-G)associated with the recall response. IFN-γ was absent or present at lowlevels in all groups, indicating that there was not a switch to a Th1response.

Example 6

This example describes data indicating that OX40 signals modulate memoryeffector T cell accumulation in secondary lymphoid organs.

To determine whether functional antigen-reactive T cells were present inmice in which OX40 signals were blocked, OVA-specific proliferation (at72 hr with 10 μg/ml OVA), and production of Th2 cytokines (IL-5; similarresults were obtained for IL-13) was measured in vitro. In brief, micewere immunized and challenged as described in Example 3. One day afterthe last OVA challenge, lung and lymph node cells were cultured inmedium alone or in the presence of increasing doses of OVA (10, 50, 100μg/ml). (Group A: Alum/OVA; Group B: Alum-OVA/IgG-OVA; Group C:Alum-OVA/RM134L-OVA).

Robust responses were detected in lung cell cultures from OVA-primed andchallenged mice but not in unprimed challenged mice (FIGS. 4A and 4B,compare grp B and grp A). These results further indicate the memoryeffector response and that a functional primary response did not resultfrom exposure to airborne antigen alone. Animals treated with anti-OX40Lduring the recall response showed little or no OVA-specific T-cellreactivity in the lungs (FIGS. 4A and 4B, grp C).

To determine whether recall responses were absent at other sites, spleenand lung draining lymph nodes were examined. OVA-reactivity wassignificantly reduced in secondary lymphoid organs after anti-OX40Ltreatment (FIGS. 4C and 4D). These results indicate that the effect ofOX40/OX40L blockade is not tissue specific but, rather, that OX40signaling is critical for development of functional memory effectorcells after memory T cells re-encounter antigen.

OX40 is only present on antigen-responding or antigen-experienced Tcells. The accumulation of OX40-expressing CD4 cells was measured overtime. In brief, peribronchial lymph node, lung, and BAL cells fromunimmunized and challenged mice, or OVA-immunized and challenged micetreated with control Ab vs. anti-OX40L Ab, were harvested before (day 0)or on the indicated days after the first OVA challenge. T cells werestained for CD4 and OX40. Total numbers of OX40+ CD4 T cells werecalculated from four mice in each group after gating on viable CD4+ Tcells.

As shown in FIG. 4 (see, also, FIG. 1), before antigen challenge only alow number of T cells expressed OX40. In contrast, after OVA challenge,a large increase was observed in the number of CD4⁺OX40⁺ cells in thebronchial lymph node (FIG. 4E), lung (FIG. 4F), and BAL (FIG. 4G) inprimed and challenged mice. The increase was far greater than inunprimed challenged mice, reflecting the responding memory effector Tcell population. The number of OX40⁺ cells in the LN peaked at day 1,whereas the number in the BAL rose progressively from day 2 over the4-day aerosol exposure. These results suggest that the initial memory Tcell response developed in the secondary lymphoid organs, and within 24hr the T cells migrated to the lung, which correlates with otherpublished data (Kaminuma et al., Eur J Immunol. (2001) 31:2669).Significantly, treatment of mice with anti-OX40L reduced the number ofCD4⁺OX40⁺ cells visualized in the lymph node at the peak of response atday 1, and subsequently. Consequently, few activated OX40⁺ T cells werethen observed in the lung and BAL.

These results suggest that OX40/OX40L interactions early in the responseof a memory T cell control their ability to expand in numbers andsurvive thereby forming a large population of memory effector T cells.

As further evidence of the role of OX40/OX40L interactions, kineticblocking studies where mice received anti-OX40L 1, 2, or 3 days afterthe initial aerosol were performed (FIGS. 4H and 4I). Although delayinganti-OX40L treatment by 1 or 2 days reduced the response by 50% and 30%,the most dramatic effect was seen when OX40/OX40L interactions wereinhibited at the time of initial encounter with recall antigen.

Example 7

This example describes data indicating that OX40-deficient OVA-specificTh2 cells do not survive efficiently in recall responses.

To further investigate the role of OX40 in recall responses ofantigen-primed Th2 cells, OVA-specific OX40-deficient CD4 cells wereproduced by crossing OX40-knockout mice to OT-II TCR transgenic mice.Naïve CD4 cells from wild-type (OX40+/+) or OX40-deficient (OX40−/−)OT-II mice were cultured in vitro with peptide and APCs under Th2 (IL-4,anti-IL-12, and anti-IFN-γ) polarizing conditions for a time period thatallows primary T cell expansion and contraction to proceed normally.Proliferation and survival were measured over 6 days and cytokineproduction (IL-4 and IL-5) measured at 40 hr. Other investigators havereported that such in vitro stimulated cells mimic in vivo generatedmemory cells (Hu et al., Nat. Immunol. (2001) 2:705, Harbertson et al.,J. Immunol. (2002) 168:1095) and can also be used in adoptive transferexperiments to directly induce lung inflammation (Cohn et al., J ExpMed. (1997) 186:1737, Hansen et al., J Clin Invest. (1999) 103:175).

Re-stimulation of primed OX40+/+ Th2 cells in vitro withOX40L-sufficient APCs resulted in proliferation, expansion, survival,and production of Th2 cytokines (FIG. 5). Primed OX40−/− T cellssecreted Th2 cytokines normally indicating that there is no apparentrole for OX40 in this T cell activity, and OX40−/− T cells alsoinitially proliferated comparably with wt T cells. However, far fewer Tcells survived in the secondary response in the absence of OX40 signals,which was also indicated by weak proliferation late in culture (FIGS. 5Aand B). Similar results were obtained if naïve T cells were stimulatedwith antigen or anti-CD3 in primary cultures.

To determine if a similar requirement for OX40 was apparent in vivoduring a recall response to aerosolized antigen, in vitro primed T cellswere labeled with CFSE, adoptively transferred into naïve micerecipients, and then the mice were challenged intranasally with OVA(FIG. 6). In brief, OVA-specific Th2 memory cells were generated invitro as described above, from wild type (OX40+/+) or OX40-deficient(OX40−/−) OT-II TCR transgenic mice. Primed T cells were labeled withCFSE and injected i.v. into naïve C57BL/6 mice. Recipient mice weresubsequently exposed to inhaled OVA or PBS on two consecutive days. 1day after the last OVA challenge, peribronchial lymph node and lung wereanalyzed by flow cytometry for division and accumulation of transferredCFSE/Vα2 positive CD4 T cells.

Challenge with PBS did not result in division (FIGS. 6A and C) orexpansion (FIGS. 6B and D) of either OX40+/+ or OX40−/− T cells indraining lymph nodes or lung. Challenge with OVA resulted in pronounceddivision of all OX40+/+ T cells. Accumulation in numbers was observed inlymph nodes and was particularly evident in lung. Correlating with thein vitro data, recovered OX40−/− T cells displayed the same divisionprofile as their wt counterparts (FIGS. 6A and C), but in totalapproximately 4-fold fewer accumulated at the end of the antigenchallenge period (FIGS. 6B and D).

These results directly mimic the data obtained by trackingOX40-expressing T cells after OX40L blockade (FIG. 4E-G). Thus, OX40signals regulate the number of memory effector T cells generated aftermemory T cells re-encounter antigen.

Example 8

This example describes data indicating that primed OX40-deficientOVA-specific Th2 cells do not efficiently promote lung inflammation.

To correlate lack of expansion/survival of memory effector cells withreduced lung inflammation, eosinophilia, lung histology and Th2cytokines were analyzed following adoptive transfer of primed OX40−/−OT-II Th2 cells (FIG. 7). In brief, OVA-specific Th2 memory cells weregenerated in vitro as described in Example 7, from wild type (OX40+/+)or OX40-deficient (OX40−/−) OT-II TCR transgenic mice. Primed T cellswere injected i.v. into naïve C57BL/6 mice. Recipient mice weresubsequently exposed to aerosolized OVA or PBS on two consecutive days,Eosinophil numbers in BAL determined 24 hr after the last OVA challenge.IL-4, IL-5, and IL-13 levels in BAL were determined from mice with wt Tcells challenged with PBS, wt T cells challenged with OVA, or OX40−/− Tcells challenged with OVA

Transfer of wild-type cells followed by repeated intranasal OVAchallenge induced profound inflammation accompanied by production of Th2cytokines in BAL (FIG. 7A, 7B). In contrast, mice receivingOX40-deficient cells exhibited only a small increase in total numbers ofeosinophils recovered from the BAL (FIG. 7A), a relatively normal lunghistology and reduced Th2 cytokines (FIG. 7B).

These results indicate that OX40 expressed on memory Th2 cell isrequired for lung inflammation.

Example 9

This example describes data indicating that OX40/OX40L interactionscontrol late secondary and tertiary recall responses to inhaled antigen.

To determine whether OX40/OX40L interactions are also critical for theresponse of memory T cells that persist for longer periods of time andsurvive following a secondary response, mice were primed for 8 weeks andanti-OX40L administered during the secondary response to aerosolizedantigen (FIG. 8A). Protocol A: In brief, unprimed control mice wereinjected i.p. with alum alone, while primed mice were sensitized withOVA adsorbed to alum. Sixty days later, all mice were challenged withaerosolized OVA on 4 consecutive days (days 60-64). Either PBS (Group A:Alum/OVA), or control IgG (Group B: Alum-OVA/IgG-OVA) or anti-OX40L(Group C: Alum-OVA/RM134L-OVA) were administered i.p. on each challengeday.

One day after the last challenge mice were sacrificed and airwayeosinophilia and Th2 cytokine production determined. Total leukocyte andeosinophil numbers were enumerated in BAL from mice in protocol A andprotocol B (below) respectively. Analysis of Th2 cytokines showed thesame profile as cell infiltration.

As before, blocking OX40 signaling strongly inhibited all aspects oflung inflammation, including total leukocyte (FIG. 8B) and eosinophil(FIG. 8C) infiltration, and production of Th2 cytokines.

In additional studies, mice were primed for 4 weeks, challenged withaerosolized antigen in a secondary response without blocking OX40L,rested for 13 weeks, and then challenged again but with anti-OX40Lblockade (FIG. 8D). Protocol B: In brief, unprimed control mice wereinjected i.p. with alum alone, while primed mice were sensitized withOVA adsorbed to alum. On days 25-29 all mice were challenged in asecondary response with aerosolized OVA. Ninety-one days later (day120), all mice were challenged in a tertiary response with aerosolizedOVA on 4 consecutive days (days 120-124). Either PBS (Group A:Alum/OVA), or control IgG (Group B: Alum-OVA/IgG-OVA) or anti-OX40L(Group C: Alum-OVA/RM134L-OVA) were administered i.p. on each challengeday.

Inhibiting OX40 signals during this tertiary response again stronglyinhibited lung inflammation (FIGS. 8E and F), with a greater than 50%reduction in cellular infiltration. As no lung inflammation was observedin unsensitized control mice repeatedly exposed to aerosolized antigen,ruling out any primary response (FIGS. 8E and F, grp A), these datademonstrate that blocking OX40/OX40L interactions severely limits recallresponse of memory Th2 populations, including responses that can persistfor extended periods of time (e.g., tertiary recall responses).

Example 10

This example describes conclusions that can be drawn from the in vivostudies employing the animal model described herein,

The data herein indicate that OX40-OX40L interactions contribute toantigen-specific memory that mediates allergic lung inflammation.Exposure of previously sensitized animals to antigen via the airways isaccompanied by large increases in the number of OX40-expressingmemory/memory effector Th2 cells, both in lungs and in secondarylymphoid organs. This effector Th2 response was associated witheosinophilia and the development of airway hyper-responsiveness. In vivostudies therefore indicate that preventing OX40-OX40L interactionsduring the memory response inhibited the Th2 response and the associatedasthmatic symptoms. Modulating peripheral acute phase inflammatoryresponses can therefore be achieved by modulating OX40-OX40Linteractions.

Analysis of BAL and dispersed lung showed that an OX40/OX40L signalinginhibitor, antibody against OX40L, reduced absolute numbers of activated(OX40⁺) memory effector T cells, consistent with OX40 involvement inmemory T cell recruitment. However, reduced numbers of activated OX40⁺ Tcells were also observed in secondary lymphoid organs, along withreduced antigen-specific activity, indicating that preventing OX40/OX40Linteractions did not simply block T cells from entering the lung. Otherstudies of lung inflammation have suggested that memory T cells do notproliferate in the lung in response to intranasal antigen challenge, butproliferate in the lymph nodes (Harris et al., J Exp Med. (2002)195:317). Moreover, prior reports show that T cell emergence in the lungis only appreciable 24-48 hr after antigen re-exposure (Kaminuma et al.,Eur J Immunol. (2001) 31:2669), consistent with the proposition thatexpansion and survival signals are required to generate a largepathogenic population. The kinetic blocking data described hereinrevealing maximal inhibition when OX40/OX40L interactions are absent atthe time of initial antigen challenge support this, along with the ideathat OX40 signals are required early (0-48 hr) and most likely providedin the secondary lymphoid organs. Further consistent with the role ofOX40 signaling regulating subsequent generation or survival of memoryeffector T cells after antigen re-activation, primed OX40-deficient Th2cells were capable of proliferating initially in the recall response,but did not subsequently accumulate in high numbers.

The data described herein is contrary to previous studies that memory Tcells largely had a reduced requirement for costimulatory signals;rather than becoming costimulation independent, T cells may, afterantigen exposure, become more reliant on other molecules such as OX40.Recent studies on an inducible Ig family member, ICOS, support thishypothesis (Gonzalo et al, Nat Immunol. (2001) 2:597). These latter datain another asthma model showed that blocking B7RP-1-ICOS interactionseffectively inhibited asthmatic symptoms at the time of allergenexposure, producing similar results as OX40 described herein. UnlikeOX40, ICOS had been proposed to primarily regulate cytokine productionrather than T cell survival (Coyle et al., Immunity (2000) 13:95). Thus,both OX40 and ICOS may act in concert but dictate distinct phases duringthe Th2 recall response.

In conclusion, OX40/OX40L interactions have a critical role in therecall response, for the subsequent activation and recruitment of memoryeffector CD4 T cells into the airway, and for the induction ofmorphological changes to the airways analogous to human asthma. SinceCD4⁺ T cells have been shown to play a critical role in both initiationand maintenance of allergic pulmonary responses these results indicatethat a viable therapeutic strategy is to inhibit OX40/OX40L interactionsin order to reduce one or more of the symptoms. For example, moleculesthat inhibit expression, activity or OX40/OX40L signaling, such asanti-OX40L antibodies, alone or in combination with other therapies.This approach has a distinct advantage over blocking production ofseveral Th2 cytokines simultaneously rather than suppressing activity,expression or signaling of a single cytokine.

What is claimed is:
 1. A method of reducing or inhibiting a recallimmune response in a mammalian subject, comprising administering anamount of an antibody that specifically binds to OX40 ligand (OX40L)sufficient to reduce or inhibit the recall immune response in themammalian subject, wherein said recall response is associated with orcauses atopic dermatitis.
 2. The method of claim 1, wherein said immuneresponse is mediated at least in part by OX40 or OX40 ligand (OX40L). 3.The method of claim 1, wherein the recall response is a secondary,tertiary or subsequent immune response to an antigen.
 4. The method ofclaim 1, wherein the mammalian subject is a human.
 5. The method ofclaim 1, wherein the antibody that specifically binds to OX40L is ahuman or humanized antibody.
 6. A method of alleviating or amelioratinga symptom associated with or caused by a recall response in a mammaliansubject, comprising administering to the mammalian subject an amount ofan antibody that specifically binds to OX40 ligand (OX40L) sufficient toalleviate or ameliorate the symptom associated with or caused by therecall response; wherein said symptom is associated with atopicdermatitis.
 7. The method of claim 6, wherein the symptom associatedwith atopic dermatitis is at least one symptom selected from the groupconsisting of rash, dermatitis, itch, edema, eczema, erythema, a lesion,a papule, a vesicle, a fissure, dryness, hyperkeratosis, keratinocyteapoptosis, hyperplasia in the dermis and/or epidermis, and necrosis ofthe skin.
 8. The method of claim 6, wherein the symptom associated withatopic dermatitis is at least one symptom in the dermis and/or epidermisselected from the group consisting of increased cytokine production,increased Th2 cytokine production, increased chemokine production,T-cell infiltration, eosinophil infiltration, leukocyte infiltration,and lymphocyte infiltration.
 9. The method of claim 6, wherein themammalian subject is a human.
 10. A method of treating, or preventingprogression or recurrence of, atopic dermatitis in a mammalian subject,comprising administering to the mammalian subject an antibody thatspecifically binds to OX40 ligand (OX40L), thereby treating, orpreventing progression or recurrence of, said atopic dermatitis.
 11. Themethod of claim 10, wherein the antibody is formulated for transdermaladministration.
 12. The method of claim 6, wherein the recall immuneresponse is a secondary, tertiary or subsequent immune response to anantigen.
 13. The method of claim 10, wherein the antibody is a humanantibody.
 14. The method of claim 13, wherein the human antibody blocksOX40/OX40L interactions.
 15. The method of claim 13, wherein the humanantibody is an IgG.
 16. The method of claim 13, wherein the humanantibody is Fab, Fab′, (Fab′)₂, Fv, Fd, scFv or sdFv.
 17. The method ofclaim 10, wherein the antibody is a humanized antibody.
 18. The methodof claim 17, wherein the humanized antibody blocks OX40/OX40Linteractions.
 19. The method of claim 17, wherein the humanized antibodyis an IgG.
 20. The method of claim 17, wherein the humanized antibody isFab, Fab′, (Fab′)₂, Fv, Fd, scFv or sdFv.